Insufficient physical activity (PA) is a leading risk factor for most chronic health conditions. Identifying patients at higher risk of these conditions due to their insufficient levels of PA is one of the highest priorities given the evidence suggesting that insufficient PA poses as much of a risk to patients? health as other established risk factors that are routinely addressed within the primary care setting (e.g., smoking, hypertension, obesity) and creates a significant financial burden on the healthcare system. Exercise is Medicine (EIM) is a global health initiative managed by the American College of Sports Medicine and American Medical Association that is committed to the belief that PA is integral to the prevention and treatment of diseases and should be regularly assessed as a vital sign and ?treated? in the healthcare setting. The Physical Activity Vital Sign (PAVS) consists of two questions: ?On average, how many days per week do you engage in moderate to strenuous exercise like a brisk walk?? and ?On average, how many minutes do you engage in exercise at this level?? The PAVS tool is optimally used in the clinic setting when it is integrated into electronic medical records (EMR) systems such as UC San Diego Health System?s Epic. Although use of the PAVS in clinical practice has been linked to favorable changes, screening alone may be insufficient for many patients. Clinically significant gains are maximized when positive screening results lead to brief PA promotion interventions. Primary care providers (PCP) are uniquely positioned to provide PA ?prescriptions? to help prepare patients for change. Evidence suggests that PA counseling is more effective when delivered by behavioral health providers, who can use motivational interviewing and shared decision- making strategies to help patients build motivation, identify barriers and solutions, and set PA goals. This study examines the barriers and facilitators of integrating the PAVS and EIM prescription with referral to primary care behavioral health (PCBH) into routine PCP visits and evaluates the program from patient, provider, and healthcare systems perspectives. I am uniquely positioned to leverage the existing PCBH program within the UC San Diego Health System to investigate the practical aspects of implementing the EIM initiative into its six primary care clinics and refining it to fit within the existing infrastructure and cultural norms of each clinic. I propose to innovatively combine two health services research approaches to accomplish my goals of implementing and continuously adapting and evaluating this initiative to fit within the evolving needs and priorities of the healthcare system. I propose a training plan comprised of a strong and committed mentorship team, formal coursework, and experiential learning. I also have the institutional support and resources necessary to conduct this study. The training goals will build upon my background in behavioral medicine and expertise in PA intervention research and extend them to health services research with a focus on implementation science and quality improvement in the context of PA screening and promotion.